Nick Clegg speaking at The Institute for Government in London today, where he signalled that key elements of control orders would be changed. Photograph: Peter Macdiarmid/PA

It is sad, indeed frightening, that in a country described as a mature democracy there still can be no serious debate about how best to protect the UK's security.

Now we have the ugly spectacle of leading Labour politicians, notably former home secretaries, praying in aid the securocracy, notably MI5, in condemning the government's as yet unannounced plans to get rid of the current system of control orders whereby people considered to be terror suspects are bound by measures described by Nick Clegg in a major speech on civil liberties on Friday as "virtual house arrest".

In an apparently unashamed attack laying himself open to a charge of sheer hypocrisy, Ed Balls, the shadow home secretary, accused Clegg of placing the preservation of the coalition government above national security. "The people I've spoken to from the security services and the police are very unconvinced that it is possible to keep our country safe without some kind of successor regime to control orders, and that is not consistent with the Liberal Democrat manifesto," Balls told the BBC on Thursday.

Lord Carlile, a Lib Dem peer who is stepping down after a number of years from his role as the independent reviewer of counter-terrorism laws, went so far as to tell the Sun earlier this week that the government would not be forgiven "if some terrible terrorism event happens". He went on: "Security and police chiefs have made clear the necessity for the orders. We ignore their advice literally at our peril."

This is not the way to conduct a debate about what to do with individuals who, according to the security services and on the basis of secret intelligence, are subjected to control orders depriving them of basic liberties.

It is scarcely surprising that the security services and police want them. Their job is to mitigate risk, as one senior counter-terrorism official puts it. Control orders are less resource-consuming than round-the-clock surveillance which is often suggested as an alternative. Surveillance, anyway, is not synonymous with control.

Yet, as Clegg also pointed out, control orders have not proved effective – some suspects have absconded. He might have added that control orders have done nothing to stop a continuing terrorist threat. Indeed, they may even have helped to encourage the radicalisation of disaffected young Muslims.

The point is not to deny the existence of a terrorist threat but to strike a balance, with the tools available in a system of criminal justice, between the protection of civil liberties and public safety in a society where, as counter-terrorism agencies themselves acknowledge, there is no such thing as "absolute security".

Contrary to what senior Labour figures and Carlile are suggesting, questioning the views and claims of the securocrats is not irresponsible. Quite the reverse. And the answer is not, as former Labour home secretary David Blunkett has suggested, more secret courts. To start with, as the civil rights group, Liberty, and others have said, the results of phone taps should be allowed as evidence in court as they are in most other countries, including the US.

Carlile, who has enjoyed access to secret information in the hands of MI5 and other agencies, has said intercept evidence wouldn't have made any difference to the case against those – now fewer than 10 – who have been subjected to control orders. But with the array of terrorism legislation now available to state prosecutors, in that case it is difficult to understand the nature of any evidence deemed to be so secret that it cannot be used in court.

Clegg, seemingly battered and bruised by an onslaught from Whitehall security chiefs, chose his words carefully. Control orders would not be removed completely because a "small number" of dangerous terror suspects could not be dealt with by the traditional justice system.

He continued: "One thing I can predict safely is that, for people who think control orders as they are, are perfect, they will be disappointed. For people who think they should be scrapped altogether, they will be disappointed as well. It's clear that there are some very hard measures in the existing control orders. I am going to change it. What I am not prepared now to say is what aspect of the regime is going to change."

We should know by this time next week, after Clegg has another bout of talks on the issue with David Cameron and the home secretary, Theresa May.